Inside Katie Holmes's Shocking Decision to Leave Tom Cruise

As one of Hollywood's most powerful stars, Tom Cruise is accustomed to being in control.

But when his wife of five years, actress Katie Holmes, filed for divorce in New York on June 29, the actor, who has been filming the sci-fi thriller Oblivion in Iceland, was caught completely off guard.

"He had no idea this was coming," a source tells PEOPLE in this week's cover story. "He's totally devastated and heartbroken."